{-# LANGUAGE MultiParamTypeClasses , FlexibleInstances, FlexibleContexts #-}
module GHC.Util.Brackets (Brackets'(..), isApp,isOpApp,isAnyApp) where

import HsSyn
import SrcLoc
import BasicTypes
import Language.Haskell.GhclibParserEx.GHC.Hs.Expr

class Brackets' a where
  remParen' :: a -> Maybe a -- Remove one paren or nothing if there is no paren.
  addParen' :: a -> a -- Write out a paren.
  -- | Is this item lexically requiring no bracketing ever i.e. is
  -- totally atomic.
  isAtom' :: a -> Bool
  -- | Is the child safe free from brackets in the parent
  -- position. Err on the side of caution, True = don't know.
  needBracket' :: Int -> a -> a -> Bool

instance Brackets' (LHsExpr GhcPs) where
  -- When GHC parses a section in concrete syntax, it will produce an
  -- 'HsPar (Section[L|R])'. There is no concrete syntax that will
  -- result in a "naked" section. Consequently, given an expression,
  -- when stripping brackets (c.f. 'Hint.Brackets'), don't remove the
  -- paren's surrounding a section - they are required.
  remParen' :: LHsExpr GhcPs -> Maybe (LHsExpr GhcPs)
remParen' (LL _ (HsPar _ (LL _ SectionL{}))) = Maybe (LHsExpr GhcPs)
forall a. Maybe a
Nothing
  remParen' (LL _ (HsPar _ (LL _ SectionR{}))) = Maybe (LHsExpr GhcPs)
forall a. Maybe a
Nothing
  remParen' (LL _ (HsPar _ x)) = LHsExpr GhcPs -> Maybe (LHsExpr GhcPs)
forall a. a -> Maybe a
Just LHsExpr GhcPs
x
  remParen' _ = Maybe (LHsExpr GhcPs)
forall a. Maybe a
Nothing

  addParen' :: LHsExpr GhcPs -> LHsExpr GhcPs
addParen' e :: LHsExpr GhcPs
e = SrcSpanLess (LHsExpr GhcPs) -> LHsExpr GhcPs
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsExpr GhcPs) -> LHsExpr GhcPs)
-> SrcSpanLess (LHsExpr GhcPs) -> LHsExpr GhcPs
forall a b. (a -> b) -> a -> b
$ XPar GhcPs -> LHsExpr GhcPs -> HsExpr GhcPs
forall p. XPar p -> LHsExpr p -> HsExpr p
HsPar NoExt
XPar GhcPs
noExt LHsExpr GhcPs
e

  isAtom' :: LHsExpr GhcPs -> Bool
isAtom' (LL _ x :: SrcSpanLess (LHsExpr GhcPs)
x) = case SrcSpanLess (LHsExpr GhcPs)
x of
      HsVar{} -> Bool
True
      HsUnboundVar{} -> Bool
True
      HsRecFld{} -> Bool
True
      HsOverLabel{} -> Bool
True
      HsIPVar{} -> Bool
True
      -- Note that sections aren't atoms (but parenthesized sections are).
      HsPar{} -> Bool
True
      ExplicitTuple{} -> Bool
True
      ExplicitSum{} -> Bool
True
      ExplicitList{} -> Bool
True
      RecordCon{} -> Bool
True
      RecordUpd{} -> Bool
True
      ArithSeq{}-> Bool
True
      HsBracket{} -> Bool
True
      HsSpliceE {} -> Bool
True
      HsOverLit _ x | Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ HsOverLit GhcPs -> Bool
forall p. HsOverLit p -> Bool
isNegativeOverLit HsOverLit GhcPs
x -> Bool
True
      HsLit _ x     | Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ HsLit GhcPs -> Bool
forall x. HsLit x -> Bool
isNegativeLit HsLit GhcPs
x     -> Bool
True
      _  -> Bool
False
      where
        isNegativeLit :: HsLit x -> Bool
isNegativeLit (HsInt _ i :: IntegralLit
i) = IntegralLit -> Bool
il_neg IntegralLit
i
        isNegativeLit (HsRat _ f :: FractionalLit
f _) = FractionalLit -> Bool
fl_neg FractionalLit
f
        isNegativeLit (HsFloatPrim _ f :: FractionalLit
f) = FractionalLit -> Bool
fl_neg FractionalLit
f
        isNegativeLit (HsDoublePrim _ f :: FractionalLit
f) = FractionalLit -> Bool
fl_neg FractionalLit
f
        isNegativeLit (HsIntPrim _ x :: Integer
x) = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< 0
        isNegativeLit (HsInt64Prim _ x :: Integer
x) = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< 0
        isNegativeLit (HsInteger _ x :: Integer
x _) = Integer
x Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
< 0
        isNegativeLit _ = Bool
False
        isNegativeOverLit :: HsOverLit p -> Bool
isNegativeOverLit OverLit {ol_val :: forall p. HsOverLit p -> OverLitVal
ol_val=HsIntegral i :: IntegralLit
i} = IntegralLit -> Bool
il_neg IntegralLit
i
        isNegativeOverLit OverLit {ol_val :: forall p. HsOverLit p -> OverLitVal
ol_val=HsFractional f :: FractionalLit
f} = FractionalLit -> Bool
fl_neg FractionalLit
f
        isNegativeOverLit _ = Bool
False
  isAtom' _ = Bool
False -- '{-# COMPLETE LL #-}'

  needBracket' :: Int -> LHsExpr GhcPs -> LHsExpr GhcPs -> Bool
needBracket' i :: Int
i parent :: LHsExpr GhcPs
parent child :: LHsExpr GhcPs
child -- Note: i is the index in children, not in the AST.
     | LHsExpr GhcPs -> Bool
forall a. Brackets' a => a -> Bool
isAtom' LHsExpr GhcPs
child = Bool
False
     | LHsExpr GhcPs -> Bool
isSection LHsExpr GhcPs
parent, LL _ HsApp{} <- LHsExpr GhcPs
child = Bool
False
     | LL _ OpApp{} <- LHsExpr GhcPs
parent, LL _ HsApp{} <- LHsExpr GhcPs
child = Bool
False
     | LL _ HsLet{} <- LHsExpr GhcPs
parent, LL _ HsApp{} <- LHsExpr GhcPs
child = Bool
False
     | LL _ HsDo{} <- LHsExpr GhcPs
parent = Bool
False
     | LL _ ExplicitList{} <- LHsExpr GhcPs
parent = Bool
False
     | LL _ ExplicitTuple{} <- LHsExpr GhcPs
parent = Bool
False
     | LL _ HsIf{} <- LHsExpr GhcPs
parent, LHsExpr GhcPs -> Bool
isAnyApp LHsExpr GhcPs
child = Bool
False
     | LL _ HsApp{} <- LHsExpr GhcPs
parent, Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== 0, LL _ HsApp{} <- LHsExpr GhcPs
child = Bool
False
     | LL _ ExprWithTySig{} <- LHsExpr GhcPs
parent, Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== 0, LHsExpr GhcPs -> Bool
isApp LHsExpr GhcPs
child = Bool
False
     | LL _ RecordCon{} <- LHsExpr GhcPs
parent = Bool
False
     | LL _ RecordUpd{} <- LHsExpr GhcPs
parent, Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
/= 0 = Bool
False
     | LL _ HsCase{} <- LHsExpr GhcPs
parent, Int
i Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
/= 0 Bool -> Bool -> Bool
|| LHsExpr GhcPs -> Bool
isAnyApp LHsExpr GhcPs
child = Bool
False
     | LL _ HsLam{} <- LHsExpr GhcPs
parent = Bool
False -- might be either the RHS of a PViewPat, or the lambda body (neither needs brackets)
     | LL _ HsPar{} <- LHsExpr GhcPs
parent = Bool
False
     | LL _ HsDo {} <- LHsExpr GhcPs
parent = Bool
False
     | Bool
otherwise = Bool
True

instance Brackets' (Pat GhcPs) where
  remParen' :: Pat GhcPs -> Maybe (Pat GhcPs)
remParen' (LL _ (ParPat _ x)) = Pat GhcPs -> Maybe (Pat GhcPs)
forall a. a -> Maybe a
Just Pat GhcPs
x
  remParen' _ = Maybe (Pat GhcPs)
forall a. Maybe a
Nothing
  addParen' :: Pat GhcPs -> Pat GhcPs
addParen' e :: Pat GhcPs
e = SrcSpanLess (Pat GhcPs) -> Pat GhcPs
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (Pat GhcPs) -> Pat GhcPs)
-> SrcSpanLess (Pat GhcPs) -> Pat GhcPs
forall a b. (a -> b) -> a -> b
$ XParPat GhcPs -> Pat GhcPs -> Pat GhcPs
forall p. XParPat p -> LPat p -> LPat p
ParPat NoExt
XParPat GhcPs
noExt Pat GhcPs
e

  isAtom' :: Pat GhcPs -> Bool
isAtom' (LL _ x :: SrcSpanLess (Pat GhcPs)
x) = case SrcSpanLess (Pat GhcPs)
x of
    ParPat{} -> Bool
True
    TuplePat{} -> Bool
True
    ListPat{} -> Bool
True
    ConPatIn _ RecCon{} -> Bool
True
    ConPatIn _ (PrefixCon []) -> Bool
True
    VarPat{} -> Bool
True
    WildPat{} -> Bool
True
    SumPat{} -> Bool
True
    AsPat{} -> Bool
True
    SplicePat{} -> Bool
True
    LitPat _ x | Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ HsLit GhcPs -> Bool
forall x. HsLit x -> Bool
isSignedLit HsLit GhcPs
x -> Bool
True
    _ -> Bool
False
    where
      isSignedLit :: HsLit x -> Bool
isSignedLit HsInt{} = Bool
True
      isSignedLit HsIntPrim{} = Bool
True
      isSignedLit HsInt64Prim{} = Bool
True
      isSignedLit HsInteger{} = Bool
True
      isSignedLit HsRat{} = Bool
True
      isSignedLit HsFloatPrim{} = Bool
True
      isSignedLit HsDoublePrim{} = Bool
True
      isSignedLit _ = Bool
False
  isAtom' _ = Bool
False -- '{-# COMPLETE LL #-}'

  needBracket' :: Int -> Pat GhcPs -> Pat GhcPs -> Bool
needBracket' _ parent :: Pat GhcPs
parent child :: Pat GhcPs
child
    | Pat GhcPs -> Bool
forall a. Brackets' a => a -> Bool
isAtom' Pat GhcPs
child = Bool
False
    | LL _ TuplePat{} <- Pat GhcPs
parent = Bool
False
    | LL _ ListPat{} <- Pat GhcPs
parent = Bool
False
    | Bool
otherwise = Bool
True

instance Brackets' (LHsType GhcPs) where
  remParen' :: LHsType GhcPs -> Maybe (LHsType GhcPs)
remParen' (LL _ (HsParTy _ x)) = LHsType GhcPs -> Maybe (LHsType GhcPs)
forall a. a -> Maybe a
Just LHsType GhcPs
x
  remParen' _ = Maybe (LHsType GhcPs)
forall a. Maybe a
Nothing
  addParen' :: LHsType GhcPs -> LHsType GhcPs
addParen' e :: LHsType GhcPs
e = SrcSpanLess (LHsType GhcPs) -> LHsType GhcPs
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsType GhcPs) -> LHsType GhcPs)
-> SrcSpanLess (LHsType GhcPs) -> LHsType GhcPs
forall a b. (a -> b) -> a -> b
$ XParTy GhcPs -> LHsType GhcPs -> HsType GhcPs
forall pass. XParTy pass -> LHsType pass -> HsType pass
HsParTy NoExt
XParTy GhcPs
noExt LHsType GhcPs
e

  isAtom' :: LHsType GhcPs -> Bool
isAtom' (LL _ x :: SrcSpanLess (LHsType GhcPs)
x) = case SrcSpanLess (LHsType GhcPs)
x of
      HsParTy{} -> Bool
True
      HsTupleTy{} -> Bool
True
      HsListTy{} -> Bool
True
      HsExplicitTupleTy{} -> Bool
True
      HsExplicitListTy{} -> Bool
True
      HsTyVar{} -> Bool
True
      HsSumTy{} -> Bool
True
      HsSpliceTy{} -> Bool
True
      HsWildCardTy{} -> Bool
True
      _ -> Bool
False
  isAtom' _ = Bool
False -- '{-# COMPLETE LL #-}'

  needBracket' :: Int -> LHsType GhcPs -> LHsType GhcPs -> Bool
needBracket' _ parent :: LHsType GhcPs
parent child :: LHsType GhcPs
child
    | LHsType GhcPs -> Bool
forall a. Brackets' a => a -> Bool
isAtom' LHsType GhcPs
child = Bool
False
-- a -> (b -> c) is not a required bracket, but useful for documentation about arity etc.
--        | TyFun{} <- parent, i == 1, TyFun{} <- child = False
    | LL _ HsFunTy{} <- LHsType GhcPs
parent, LL _ HsAppTy{} <- LHsType GhcPs
child = Bool
False
    | LL _ HsTupleTy{} <- LHsType GhcPs
parent = Bool
False
    | LL _ HsListTy{} <- LHsType GhcPs
parent = Bool
False
    | LL _ HsExplicitTupleTy{} <- LHsType GhcPs
parent = Bool
False
    | LL _ HsListTy{} <- LHsType GhcPs
parent = Bool
False
    | LL _ HsExplicitListTy{} <- LHsType GhcPs
parent = Bool
False
    | LL _ HsOpTy{} <- LHsType GhcPs
parent, LL _ HsAppTy{} <- LHsType GhcPs
child = Bool
False
    | LL _ HsParTy{} <- LHsType GhcPs
parent = Bool
False
    | Bool
otherwise = Bool
True